It is conventional to store medicaments, drugs or vaccines in a sealed cartridge or other container for later use. Such medicaments, drugs or vaccines may be in liquid or dry or powdered form to increase the shelf life of the drugs and reduce inventory space. Such dry or powdered medicaments, drugs or vaccines are generally stored in a sealed cartridge and reconstituted in liquid form for administration to a patient by adding a diluent or solvent. A conventional medical cartridge for storing medicaments generally includes an open end, a radial rim portion surrounding the open end and a reduced diameter neck portion adjacent the rim portion. The cartridge is conventionally sealed with an elastomeric stopper or septum which generally includes a central portion overlying the open end of the cartridge and a planar radial rim portion which overlies the cartridge rim. The stopper is normally secured to the cartridge with a thin malleable metal cap, such as aluminum. The aluminum cap includes a tubular portion which surrounds the rim portions of the stopper and cartridge, an inwardly projecting annular portion which overlies the rim portion of the stopper and a distal end portion which is crimped radially into the neck of the cartridge beneath the rim portion. Because aluminum is malleable, the collar accommodates the buildup of tolerances of the dimensions of the stopper and rim. The dimensions and tolerances of standard cartridges and stoppers are set by the International Standards Organization (ISO).
The radial portion of the aluminum cap which overlies the stopper rim portion may be closed, in which case the aluminum cap is removed by “peeling” the aluminum cap from the cartridge. A pre-slit tab located in the middle area may be provided which overlies the cartridge rim, permitting the cap to be torn from the top and peeled from the cartridge prior to use. This closed embodiment of an aluminum cap has several disadvantages. First, the tearing of the metal cap creates sharp edges which may cut or damage sterile gloves and cut the person administering the drug, thereby exposing both the healthcare worker and the patient to disease and contamination of the drug. Second, the tearing of the aluminum cap generates metal particles which may also contaminate the drug, medicament or vaccine. The dangers associated with the tearing of an aluminum cap has been solved in part by adding a “flip-off” plastic cap. In one such embodiment, the aluminum collar includes a central opening and a shallow plastic cup-shaped cap is received over the aluminum collar having a central projecting riveting portion which is received and secured in the central opening of the aluminum collar. The plastic cap is then removed by forcing the flip-off cap away from the aluminum collar, which tears an annular serrated portion surrounding the central opening and exposes an opening in the collar for receipt of a needle cannula or the like. This embodiment reduces but does not eliminate the possibility of tearing the sterile gloves of the healthcare worker. More importantly, however, aluminum dust is still created during crimping of the aluminum cap which may contaminate the medicament, drug or vaccine contained in the cartridge. It is also important to note that metallic dust is also created simply by forming and affixing the aluminum cap or collar to the cartridge because aluminum dust is created in forming the aluminum collar, crimping of the collar and removal.
Various types of medical cartridges are now available for delivery of a medicament, drug or vaccine. A medical cartridge includes a tubular barrel portion, typically formed of glass, having open proximal and distal ends, wherein the proximal end includes a radial rim portion and a reduced diameter neck portion adjacent the rim portion. The proximal open end of the cartridge is sealed with an elastomeric stopper having a central portion overlying the open proximal end of the cartridge and a rim portion overlying the rim portion of the cartridge. The proximal open end of the cartridge is sealed with a malleable metal cap generally formed of aluminum including a tubular collar portion surrounding the rim portion of the cartridge which is crimped around the rim portion into the neck portion of the cartridge. The cap further includes a radial portion overlying the rim portion of the elastomeric stopper and the cap generally includes a central circular opening coaxially aligned with the opening through the proximal end of the cartridge. The cap is secured to the proximal end of the cartridge by resiliently compressing the radial portion of the cap against the rim portion of the elastomeric stopper and crimping the free end of the collar portion into the neck portion of the cartridge.
The open distal end of the cartridge is sealed with a stopper, generally formed of an elastomeric material, which serves as a plunger to propel the fluid through the proximal open end of the cartridge. The cartridge may be utilized in a delivery pen, for example, as disclosed in U.S. Pat. No. 5,549,575 assigned to the assignee of the present application, the disclosure which is incorporated herein by reference. A delivery pen typically includes a needle assembly received on the proximal end of the body portion having a needle cannula which pierces the elastomeric stopper or septum which seals the proximal end of the cartridge and the stopper in the distal end of the cartridge is then driven through the barrel portion to dispense a liquid medicament, drug or vaccine through the needle cannula during an injection. The medical cartridge may also include a third stopper centrally located within the barrel portion which, during injection, intermixes the substances contained in the barrel portion between the stoppers as discussed further below.
The need therefore remains for a method of sealing cartridges and other medical containers which may be utilized for sealing conventional medical cartridges, which assures sealing of the container and which achieves a good level of cleanliness, without metal particles or dust which may contaminate the medicament, drug or vaccine, and which does not expose the health care worker to sharp edges. The method of sealing a medical container of this invention solves these problems and permits sealing of medical containers in an aseptic environment.